Facts

 

ALUMINUM VS STEEL CONNECTING RODS


Oh boy...the forever on-going debate and seemingly the most discussed topic in the high performance world. Shall we even go there?

Sure...but we'll intro this section by saying this is OUR opinion on the subject.


Aluminum rods act much like a "shock absorber" under load and will suck up the pounding the piston is transmitting to both the crank and bearing during the power cycle. Especially on the exhaust stroke when the bolts are really being put to the test as they have to hang onto that rod for dear life. Aluminum is good!


It is for this very reason (along with a lighter rotational assembly) why EVERY blown car, nitro, Top Fuel, Modified or otherwise use aluminum rods...they relieve a lot of the stress the bearings see in these crazy HP steroid monsters because of the rod's shock absorbing qualities. Again, aluminum is good!


But as with anything in making HP, there's always a price...the rods are changed out often. But at this extreme power level, the performance advantages gained are well worth the cost and maintenance for these guys.

 

 

 

 

KITTIE YOGA STRETCH


HOW LONG DO THEY LAST?


Yes, these rods will stretch. Guess what? Steel rods do as well. Let’s do a little record straightening here…


ALL connecting rods stretch when under load…albeit aluminum stretches about .010″ more than steel. But both alloys will return to their original size when the load is removed. The point they don’t return to their original size, is when the metal has been fatigued beyond its limitations. This is called deformation. Much like when a bolt has been stretched beyond its yield…the bolt will not return to its original length. Junk it…it can no longer do the job that it was designed to do.


So backing up a bit, why does a Nitro car change its rods only after 10 passes? That’s because the rods has been stretched to the point of no return.  Major pounding…major RPMs…Mach 1 speeds. The rod has now seen its limitations to maintain its dimensions. Junk it…it can no longer do the job it was designed to do.


This “stretch” is inherent to all extreme power makers…a known fact with builders and nothing new and/or mysterious. How to combat this? When we designed our rods, we accounted for this stretch by designing the C-to-C length .010″ under, so when assembling, their expansion actually will NOT have to be accounted for when setting your piston-to-valve clearance. Viola! One less brain wrinkle made. Aint it cool?

Somewhat of a loaded question with many answers. We’ll speak it as we see it. It really is very simple.


The amount of life you can get from an aluminum rod is entirely up to the application you’re using it in. Folks tend to group all of these apps into one. Not a fair nor accurate thing to do. Don’t be an ignoramus.


A blown alcohol car will possibly get around 20 passes with a set of aluminum rods. A little bracket racer car uses them the entire season…and often times, for multiple seasons. A weekend tinker toy with quick jaunts to Foodland and the GF’s past 3am for a quickie will last 20k plus miles.


Bottom-line: it all really depends on how hard they are being pounded on.


So, you want REAL-WORLD facts? Alright. We can share a few of our customer’s past experiences while using our rods:

Over 319 highly abusive passes spinning them at over 10 grand through the traps in a consistent mid 8 second car.

Over 200 passes for three seasons in a 7 second car. Approx 250 horse per bore.


These big tid bits are sort of a big deal

 


The bottom bottom-line: With all factors being the same, be it a bracket car or a good ol’ boy pick ’em up truck, these rods are THE industry leader when it comes to longevity for their chosen application. Period.

 

 

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